Voice Test Platform (VTP)

The Voice Test Platform (VTP) tests the continuity, and voice quality of Circuit-Switched (CS) and Packet-Switched (PS) voice calls. The platform verifies the speech path and, in each direction, is capable of transmitting reference sampled analog voice files from disk and recording their corresponding versions on disk after passing through the CS or PS networks. Multiple simultaneous calls are supported. The VTP includes a licensed Perceptual Objective Listening Quality Assessment (POLQA) algorithm to analyze the voice quality of recorded audio.

The Python-based script engine (CPython 3.5.3) in the VTP allows for automated, application-specific testing, carried out with test scripts. In addition to controlling the internal voice servers, the script engine can interface to other network elements such as a User Terminal, Network Emulator, or Physical Layer Tester to test end-to-end call scenarios. Users can quickly build test cases, using the familiar Python script language with a rich library of call processing APIs included with the platform. The analog and VoIP channels are highly configurable, allowing fine control over voice call test scenarios. The VoIP channels are supported by a full featured SIP stack, providing SIP Agent server and client features and a variety of codecs including G.729 and Opus. The FXO channels operate with North American and ITU Standards and variants covering most signalling and supervision features.